Folding gantry for cranes



March 1956 J. E. CALLOUETTE ETAL 2,738,384

FOLDING GANTRY FOR CRANES 4 Sheets-Sheet 1 Filed Jan. 14, 1953 March1955 J. E. CALLOUETTE ETAL 2,738,884

FOLDING GANTRY FOR CRANES 4 Sheets-Sheet 2 Filed Jan. 14, 1955 March 0,1956 J. ECALLOUETTE ETAL 2,738,884

FOLDING GANTRY FOR CRANES Filed Jan. 14, 1953 4 Sheets-Sheet 3 March1955 J. E. CALLOUETTE ETAL 2,738,884

FOLDING GANTRY FOR CRANES Filed Jan. 14, 1953 4 Sheets-Sheet 4 IN V ENTOR-3. Job/7 f. C0//0uef/ e ano United States O FOLDING GANTRY FORCRANES I John E. Callouette and Revilo F. Kinney, Marion, OhioApplication January 14, 1953, Serial No. 331,163

Claims. or. 212-59 7 The invention relates generally to materialhandling power cranes, and more particularly to the mechanism forproviding a new improved rapid folding boom supporting gantry.

This rapid folding gantryis composed of flexible back legs which make upthe sloping member and are pivotally connected to the upper rearhorizontal member or aft support of a stationary frame mounted on themachinery deck. The front ends of these flexible legs are pivotallyconnected to the top of the front telescoping legs or the verticalmember with yoke-like feet supported on and latched to the fore supporton said frame which operates with the gantry in telescopic extendedposition. This vertical member can be guided and controlled into afolded position and returned to the extended positions by raising andlowering the boom by means of a boomhoist line wound upon a conventionalcontrolled winch. Two winches may be employed if greater speed isdesired. Both winches would be powered from a common source, such as aninternal combustion engine mounted on the deck of the crane.

One of the objects in view is to provide improved means for folding andextending the gantry by controlled power through operating the boom,necessitating only human guidance and control instead of the present daymethods that require human lifting of gantry parts to extend and fold.

Another object is to provide means for lowering the gantry and boom tothe elevation to and below the top of the cab to obtain overheadclearance, more quickly, and with greater safety and with the leastamount of human effort.

Still another object is the provision of means for maintaining themaximum angle between the boomhoist line and the boom, thus keeping theline and boom loads to a minimum for all working angles of the boom,accomplished by the telescoping action of the front legs of the gantry.

Another object is the provision of latch pins to latch the yoke-likefeet of the male member of the telescoping front legs of the gantry tothe said frame, which pins when removed to unlatch the feet of the frontlegs, are used to latch the front legs from telescoping, so that thefeet of the front legs will lift clear of the front member of supportingframe when the boom is lifted to a high position, permitting the frontand back legs to automatically fold progressively towards parallelpositions as the boom is lowered into a horizontal plane at cab height.

Another object is the provision of ellipsoidal saddles mounted on upperfront frame member upon whichthe flexible back leg of the gantry rides,being longer than the upper side members of the frame, when the boom andgantry are lowered to the elevation of the top of the cab.

Another object is the provision of inverted channel upper sidesupporting frame members which act as guides to automatically fold thefront legs back and under as the boom is lowered with the feet of thefront legs unlatched,

the telescopic rearwardly.

' Other novel features of construction and arrangement of parts willappear from the following description and claims.

In the accompanying drawings, wherein is illustrated a practicalembodiment of the principles of the invention:

Fig. 1 is a side elevation illustrating the structure of a crawler cranewith the gantry extended to its initial working position. 1

Fig. 2 is an isometric illustration of the gantry extended to itsinitial working position as shown in Fig. 1.

Fig. 3 is a side elevation illustrating the structure of a- Fig. 8 is anisometric illustration of the folded gantryas shown in Fig. 7. 8

Referring to the drawings, 20 indicates the machinery deck of the crane,which, as is common practice, is rotatably mounted on a vertical axis onan undercarriage of either portable frame, truck or crawler, andprovided with a motor for selectively propelling the carrier, swingingthe superstructure, hoisting a load and operating the boom and gantry.21 indicates the stationary machine side frames, which are also thefront legs of the stationary frame supports of the folding gantry or Aframe. The back members 22 of the stationary frame and the upper sidemembers 23, together with the back upper horizontal member 24 and thefront upper horizontal member 25 constitute the supports and completethe stationary frame.

26 indicates the flexible back legs on the rear member of the foldinggantry and the telescoping front legs on the front member 27. 28 is thecrossbracing of the female members of the telescoping front legs orfront member. Latch pins 29 are inserted through holes at the ends ofthe bifurcated foot to prevent the male members of the front legs fromlosing their footing when the boom is raised to a high enough positionto extend the telescoping of the front legs. The telescoping front legshave the holes 30 into which the pins 29 are transferred to unlatch thefeet of the front legs from the support shaft 19 and latch the frontlegs to prevent their telescoping and to allow them to raise their feetoff the shaft 19 as the boom is raised to a high position.

The support shaft 19 forms the fore support for the folding gantry Aframe and the back member 24 forms its aft support. It will be notedthat these fore and aft supports are spaced closer together than thelength of the rear member or legs 26, as the sheaves 34 are beyond thesaddle members 31 when the gantry is folded as shown in Fig. 8. Thefront member 27 slopes back to connect with the rear member 26 at theapex. Thus, when the pins 29 are withdrawn from the bifurcated feet ofthe legs 27 and are inserted in the holes 30 they prevent the frontmember from telescoping. The boom is raised as shown in Figs. 5 and 6,and the front member 27 hangs vertically and not over the shaft. As theboom is lowered, the front members 27 are pushed back with thebifurcated feet engaging the horizontal flange of the angle members 23which guide them rearwardly to the lowered and folded position as shownin Fig. 8. The boom may be raised to unfold and extend the gantry atwhich time the bifurcated Patented Mar. 20, 1956.

action latched and the front legsswung.

illustrating the structure of a.

feet are guided onto the shaft and latched as shown in Fig. 2. a

32 indicates a conventional crane boom operated by the boomhoist andgantry operating cable 33 which is woven over the boomhoist sheaves 34.The ends of the cable 33 are attached to and wound upon theboomhoist'winches 35 and 36 which are'hsedwhen greater-speed is desired,for raising and lowering the boom and :for folding "the rapid foldinggantry.

We claim:

1. Arapid folding gantry for a hoist comprising a machinery deck, 'aboom pivoted 'to the front end of said deck, supper-ts on said deck tothe-rear of said boom pivot, a fore mounting and an aft mounting on saidsupports, a folda-ble fiyinggantry having front legs and rear legspivotally connected together at their upper ends to form anapex-saidfrOntlegs having telescopic sections, a detachablep'in to lockthe telescopic sections of the front legs together, sheave means on saidapex, detachable means to releasably connect the-bottom of the frontlegs to said 'fore mounting, 'pivotmeans to-pivo'tally connect thebottom of said rear legs to said a'ft mounting, a boom hoist'line reevedover said sheave means and connected to said boom, winch means carriedby said machinery deck-to operate said boom hoist line to raise andlower the boom, the length from the attachment of said boom hoist lineto the boom pivot being proportioned relative to the position of saidaft mounting to provide a straight line of force between the attachmentof said boom hoist line with the boom and said aft mounting, whichstraight line-oh force lies-above the normal position 'of saidapart whensaid boom is elevated to provide a force to lift the locked telescopicsections of the front legs of the flying gantry and permit them to bedisconnected from the fore mounting of said supports and folded backwhen the boom is lowered.

2. The structure of claim 1 is characterized in that the telescopicsections of said front legs of the flying gantry are expandable whenunlocked to maintain said apex in alignment with said force linealo'n'gsaid boomhoist line.

3. The structure of claim l is characterized in that saiddetachablemeansreleasably connecting the bottom of the front legs tosaidfore mounting are bifurcated members having pins to hold them frombecoming detached.

4. The structure of claim 1 is characterized in that said rear legs areflexible intermediate of the ends thereof.

5. The structure of claim 4 which also'includessaddle means carried bysaid supportsto receive the flexible rear legs of the flying gantry whenfolded.

References Cited in theLfile of this patent UNITED STATES PATENTS2,186,372 Elg'h "Jan. 9, 1940v 2,335,858 Huston Dec. 7, 1943 2,383,426Tanenbaum Aug. 21, 1945 2,420,163 BOrSini May '6, 1947

